摘要: Brood parasitic birds lay eggs in the nests of other birds, and the parasitized hosts can reduce the cost of raising unrelated offspring through the recognition of parasitic eggs. Hosts can adopt vision-based cognitive mechanisms to recognize foreign eggs by comparing the colors of foreign and host eggs. However, there is currently no uniform conclusion as to whether this comparison involves the single or multiple threshold decision rules. In this study, we tested both hypotheses by adding model eggs of different colors to the nests of Barn Swallows(Hirundo rustica) of two geographical populations breeding in Hainan and Heilongjiang Provinces in China. Results showed that Barn Swallows rejected more white model eggs(moderate mimetic to their own eggs) and blue model eggs(highly non-mimetic eggs with shorter reflectance spectrum) than red model eggs(highly nonmimetic eggs with longer reflectance spectrum). There was no difference in the rejection rate of model eggs between the two populations of Barn Swallows, and clutch size was not a factor affecting egg recognition. Our results are consistent with the single rejection threshold model. This study provides strong experimental evidence that the color of model eggs can has an important effect on egg recognition in Barn Swallows, opening up new avenues to uncover the evolution of cuckoo egg mimicry and explore the cognitive mechanisms underlying the visual recognition of foreign eggs by hosts.

摘要: Charismatic species are often reported by the media, providing information for detecting population status and public perception. To identify the number and distribution of free-living Black Swan(Cygnus atratus), a charismatic alien species in Chinese mainland and to detect the public and the media attitudes to the species, we analyzed the reports and emotional tendency from media coverage in 2000–2022 using manual reading, crawler extraction and latent Dirichlet allocation. A total of 6654 Black Swans were reported at 711 sites, including 147 individuals at 30 nature reserves. Successful breeding was reported at one-fourth of the total sites, including five nature reserves. The proportion of positive emotional tendency to Black Swans was overwhelming in the reports and was higher than that to alien species in general, suggesting that the public and the media are unaware of the risk of biological invasion. Effective management of invasive species requires the media clarifies the invasion risk of charismatic alien species. Promoting the unity between the harmfulness of abstract concept of alien species and the charisma of a specific alien species among the public help effective management.

摘要: Embryonic development is a critical period for phenotype formation. Environmental variation during embryonic development can induce changes in postnatal phenotypes of animals. The thyroxine secretion and aerobic metabolic activity of small birds are important phenotypes closely related to their winter survival. In the context of climate change, it is necessary to determine whether temperature variation during incubation in birds leads to developmental plasticity of these cold responsive phenotypes. We incubated Japanese Quail(Coturnix japonica) eggs at 36.8 ℃, 37.8 ℃, and 38.8 ℃, and raised the chicks to 35-day old at 22 ℃ with same raising conditions, then all the quails were exposed to gradually temperature dropping environment(from 15 ℃ to 0 ℃). After cold treatment, serum T3 level, resting metabolic rate, skeletal muscle and liver metabolomes of the birds were measured. The serum T3 levels were significantly lower in the 38.8 ℃ group and significantly higher in the 36.8 ℃ group compared to the 37.8 ℃ group. The metabolic rate in the 38.8 ℃ group was significantly lower compared to the 37.8 ℃ group. Compared with the 37.8 ℃ group, metabolites involved in the tricarboxylic acid cycle in the liver were significantly lower in the 38.8 ℃ group, and metabolites related to lipid oxidation metabolism and fatty acid biosynthesis were significantly lower in the skeletal muscles in the 38.8 ℃ group but significantly higher in the 36.8 ℃ group. These results indicate that incubation temperature variation can lead to developmental plasticity in cold responsive physiological phenotypes. Higher incubation temperature may impair the capacity of birds coping with cold challenge.

摘要: Females actively seek extra-pair paternity(EPP) to acquire a fitness advantage for their offspring. The “contextdependence hypothesis” posits that female extra-pair mate choice has plasticity in response to environmental conditions, and therefore magnitude of female genetic benefits from EPP depends on the environmental variation. Furthermore, chronic heavy metal pollution can cause adverse effects on fitness-related traits of wild birds. However, few studies were available on the interactions between heavy metal pollution and EPP. We selected an area that was contaminated by heavy metals for more than 60 years(Baiyin, BY), a relatively unpolluted area(Liujiaxia, LJX), and Tree Sparrows(Passer montanus) as study species to explore the response of female extrapair mate choice and genetic benefits from EPP to heavy metal pollution in socially monogamous birds. The relatedness between social mates and extra-pair mates was investigated. Additionally, we compared the body size and heterozygosity of extra-pair offspring(EPO), within-pair offspring(WPO), social males and extra-pair males from the two Tree Sparrow populations. We found that at BY, female Tree Sparrows tended to choose extra-pair males with larger body size and lower genetic similarity, thereby producing higher heterozygosity and larger body size of EPO compared with those of WPO. However, no similar phenomenon was observed in the Tree Sparrow population from LJX. In addition, there was a significant interaction between population and paternity in the analyses of the fitness-related traits, suggesting that environmental variation could affect female genetic benefits from EPP. This study confirmed the existence of presumed interactions between environmental pollution and EPP within the natural population of socially monogamous Tree Sparrows. Our findings shed lights on the possible effects of long-term environmental stress on mating system in wild birds.

摘要: Variations in host traits that influence their exposure and susceptibility may impact probability of vectortransmitted diseases.Therefore,identifying the predictors of infection probability is necessary to understand the risk of disease outbreaks during expanding environmental perturbation.Here,we conducted a large survey based on microscopic examination and molecular analysis of haemosporidian parasite infection in raptors rescued at the Beijing Raptor Rescue Centre.Combining these data with biological and ecological variables of the raptors,we determined predictors that affect the probability of haemosporidian infection using generalized linear mixed models and multimodel inference.Our results showed that infection probability exhibited considerable variation across host species in raptors,and body mass,sex,and evolutionary history played relatively weaker roles in driving infection probability.Instead,activity pattern,age,geographic range size,migration distance,and nest type were important predictors of the probability of haemosporidian infection,and the role of each predictor differed in the three main haemosporidian genera(Plasmodium,Haemoproteus,and Leucocytozoon).This macro-ecological analysis will add to our understanding of host traits that influence the probability of avian haemosporidian infection and will help inform risk of emerging diseases.

摘要: The House Martin(Delichon urbicum) is a common farmland bird species in the European landscape,yet its population numbers are currently in decline.However,it is not yet sufficiently explained why this long-term decline occurs.To fill this gap in our knowledge,we investigated how land cover composition affects the abundance of House Martins on the landscape scale by using nationwide citizen science data.Utilizing a generalised linear mixed-effect model(GLMM),we evaluated 12,094 records from the Czech Republic spanning 2009-2017.Our analysis underscores the significance of land cover type in shaping House Martin abundance.More specifically,our results indicate that within agricultural land covers "naturally managed arable lands" exhibited significant positive effect,while forests,orchards,and vineyards were deemed less favourable for House Martin populations.Within urban land covers,we found a clear distinction in the impact on House Martin populations,with a positive effect observed in urban infrastructure,development areas,and post-industrial sites(i.e.,UrbanAreas),while an indifferent impact was noted within urban green spaces and landscaped areas(i.e.,GreenUrban).Notably,our findings suggest that the simple spatial,age,and species structure typical of forests in Europe,and similarly,the uniform structure of parks and gardens,may be responsible for the decline in the abundance of the House Martin.We advocate for the preservation or enhancement of urban greenery,expansion of natural vegetation in rural areas and adoption of ecological management practices in orchards and vineyards to mitigate further declines in House Martin populations.

摘要: Management under ecological schemes and increasing habitat heterogeneity,are essential for enhancing biodiversity in vineyards.Birds provide several contributions to agriculture,for example pest control,recreation and enhancing human mental health,and have intrinsic value.Birds are also ideal model organisms because they are easy to survey,and species respond differently to agricultural land use at different scales.Vegetated borders of crops are key for many species of birds,and distance to the border have been found to be an important factor in vineyard-dominated agroecosystems.We evaluate if there are differences in the bird assemblage,between the interior compared to borders within vineyards,using a hierarchical community occupancy model.We hypothesized that occupancy of birds is greater in environments with greater heterogeneity,which in this study was considered to be contributed by the proximity to vegetated corridors.We expected that vineyard borders close to corridors will have higher bird occupancy than the center of the vineyard.The research was conducted in three vineyards with biodiversity-friendly management practices,in Gualtallary,Mendoza,Argentina.Bird surveys were conducted over three breeding seasons from 2018 to 2020.Occupancy and richness of the bird community was more closely associated with the borders adjacent to the corridors than with the interior of the vineyards,as we initially predicted,although the assemblage of birds did not differ much.More than 75% of the registered species consume exclusively or partially invertebrates.Biodiversity-friendly management and ecological schemes,together with vegetated corridors provide multiple benefits for biodiversity conservation.These approaches not only minimize the use of agrochemicals but also prioritize soil cover with spontaneous vegetation,which supports a diverse community of insectivorous bird species,potentially contributing to pest control.

摘要: Nestling growth of birds can be affected by weather fluctuations.In general,it is expected that higher temperatures favor growth by improving food availability and nestling metabolism,while rain hinders it by reducing foraging efficiency.However,most of these patterns have been described in insectivorous cavity-nesting birds in temperate forests.We tested these predictions in two neotropical grassland ground-nesting birds with contrasting nestling diets and therefore potentially different responses to weather.We measured nestlings of the Hellmayr's Pipit(Anthus hellmayri,an insectivorous passerine) and the Grassland Yellow-Finch(Sicalis luteola,which feeds its nestlings exclusively with seeds) during three breeding seasons(2017-2020) in central-eastern Argentina.We took measurements of tarsus and body mass,modeled growth curves using nonlinear mixed-effects models,and evaluated the effects of minimum daily temperature and precipitation during the growth period and the 30 days prior to hatching.For pipits(60 nestlings from 21 nests),minimum temperatures during the growth period were positively associated with tarsus and body mass asymptotes.Also,there was a positive association between precipitation during the pre-hatching period and tarsus asymptote.Conversely,none of the weather variables analyzed had significant effects on nestling growth of finches(131 nestlings from 35 nests).Dietary contrast between species may explain the different results.Arthropod activity and abundance can be affected by weather variations within the span of a breeding season,whereas seeds may depend on conditions from previous years,making the effects harder to detect.Fledglings with reduced asymptotic size can have reduced chances of survival.Hence,pipit populations could be impacted if they experience cold and dry conditions during their breeding season,which is of major relevance in the current context of climate change.

摘要: Beta diversity,the variation of community composition among sites,bridges alpha and gamma diversity and can reveal the mechanisms of community assembly through applying distance-decay models and/or partitioning beta diversity into turnover and nestedness components from functional and phylogenetic perspectives.Mountains as the most natural experiment system provide good opportunities for exploring beta diversity patterns and the underlying ecological processes.Here,we simultaneously consider distance-decay models and multiple dimensions of beta diversity to examine spatial variations of bird communities,and to evaluate the relative importance of niche-based and neutral community assembly mechanisms along a 3600-m elevational gradient in the central Himalayas,China.Our results showed that species turnover dominates taxonomic,functional,and phylogenetic beta diversity.We observed strongest evidence of spatial distance decays in taxonomic similarities of birds,followed by its phylogenetic and functional analogues.Turnover component was highest in taxonomic beta diversity,while nestedness component was highest in functional beta diversity.Further,all correlations of assemblage similarity with climatic distance were higher than that with spatial distances.Standardized values of overall taxonomic,functional,and phylogenetic beta diversity and their turnover components increase with increasing elevational distance,while the standardized values of taxonomic and phylogenetic nestedness decreased with increasing elevational distance.Our results highlighted the niche-based deterministic processes in shaping elevational bird diversity patterns that were determined by the relative roles of decreasing trend of environmental filtering and increasing trend of limiting similarity along elevation distances.

摘要: In many songbird species,birdsong features phonological syntax,meaning that the units within their vocal sequences are ordered in a non-random way that adheres to a rule.While such syntactical patterns have been richly described in many species,comparatively little is known about how those patterns contribute to song achieving its important functions.For each of song's main functions,territorial defense and mate attraction,evidence of a role for syntax is limited.One species for which syntax has been thoroughly described is the Hermit Thrush(Catharus guttatus),which presents song types from their repertoires in a semi-predictable order and,in doing so,rapidly cycle up and down the frequency spectrum.The objective of the present study was to explore the importance of song syntax in the Hermit Thrush through a within-subject examination of how measures of syntax,such as the predictability of song type order within song sequences,shift over the breeding season.We hypothesized that,if such syntactical characteristics are important to breeding behaviour,they would be most prominent at the start of the breeding season when activity associated with territory establishment and mate attraction is most intense.Analysis revealed that,as predicted,the rigidness of song type ordering within sequences was highest at the start of the season and declined thereafter.That song type sequences were most predictable at the vitally important early part of the breeding season fit our hypothesis that this aspect of song syntax is important to song's functions related to territory establishment and/or mate attraction.Future work will clarify whether that role relates to one of song's two main functions or serves song transmission in some broader way.